00:01
All right.
00:02
So for this question, we are going to be looking at freshwater fish.
00:07
And we're going to be looking at what happens to their water intake.
00:11
Do they have too much? do they not have enough? what happens to their ions? so you remember sodium, potassium, chloride, what happens to all that stuff in the water that they take in? and so to start, i'm going to do a very crude drawing of a fish, a classic drawing.
00:30
And remember fish have gills which they use to breathe so if we zoom in on these gills let's just look at them like a cell so each one of these gills has thousands maybe even millions of cells and we'll just draw a circular cell and so what happens is because they're in fresh water remember freshwater means that it doesn't have the salt content like the marine ocean so because these cells are sitting in this fresh water, and we'll make this kind of blue all around, because they're sitting in this water, they actually have more solutes or more ions on the inside than there are in the outside.
01:19
So we'll make ions in red.
01:21
We'll just make red little circles.
01:23
They have more stuff floating around on the inside because remember the outside is freshwater.
01:29
So the cell is actually saltier, we could call it.
01:34
And so what happens is when this fish over here, when he's just swimming through the ocean, his cells will actually start to take in water.
01:49
Because remember, water always moves from where there is more of it to where there is less of it, which is here in the middle.
01:58
So there's less water here in the middle and there's more solutes.
02:05
So water is attracted to that.
02:07
So the fish now has a problem.
02:10
The fish is getting too much water.
02:14
So fish is getting too much water.
02:32
And so this is a problem because we can get dehydrated, but we can also drink too much water...